Wildcat04
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Homework Statement
Calculate flow velocity and magnitude at a point (2,-2)
Sink at origin with strength 20 m2/s
Vortex at (0,2) with strength 25 m2/s
Uniform flow in +x with strength of 10 m/s
The Attempt at a Solution
\phi = \phi1 + \phi2 + \phi3
\phi1 = -Ux = -U r cos(\theta)
\phi2 = -\mus ln r
\phi3 = \muv \theta
vr = d\phi/dr
=-U * cos \theta - \mus * (1/r)
=-10 cos(\pi/4) - 20 / 2.83
=-14.14
v\phi = (1/r) d\phi / dr
= (1/r) (-14.14)
= -5
u = .5 (14.14) + .5(5) = -9.57
v = -.5(14.14) + .5(5) = 4.57
I know that I have butchered this because the solutions is supposed to be
V = 12.5 m/s
u = 10 m/s
v = 7.5 m/s
\alpha = 37 degrees
Could someone please point out the obvious flaw in my logic and point me in the right direction?
Thank you very much in advance!